NS by Example 笔记（16）Web Server Example

Web Server Example

(Obsolete: work with ns-2.1b4a)

 

Web Server模拟脚本和网络拓扑。 脚本文件"ex-web.tcl"和"dumbbell.tcl" (This example is from the 5th VINT/NS Simulator Tutorial/Workshop). Note that you should change the path for "http-mod.tcl" at the begining of the script to an appropriate one to make it run on your machine.

 

 
Figure 34. Web server simulation network topology

 

ex-web.tcl

# Initial setup
source ~/ns-allinone-2.1b4a/ns-2/tcl/http/http-mod.tcl
source dumbbell.tcl
global num_node n

set ns [new Simulator]
$ns set-address 7 24     ;# set-address <bits for node address> <bits for port>

# set up colors for nam 
for {set i 1} {$i <= 30} {incr i} {
    set color [expr $i % 6]
    if {$color == 0} {
	$ns color $i blue
    } elseif {$color == 1} {
	$ns color $i red
    } elseif {$color == 2} {
	$ns color $i green
    } elseif {$color == 3} {
	$ns color $i yellow
    } elseif {$color == 4} {
	$ns color $i brown
    } elseif {$color == 5} {
	$ns color $i black
    }
}

# Create nam trace and generic packet trace
$ns namtrace-all [open out.nam w]
# trace-all is the generic trace we've been using
$ns trace-all [open out.tr w]

create_topology

########################### Modify From Here #####################
## Number of Pages per Session
set numPage 10
set httpSession1 [new HttpSession $ns $numPage [$ns picksrc]]
set httpSession2 [new HttpSession $ns $numPage [$ns picksrc]]

## Inter-Page Interval
## Number of Objects per Page
## Inter-Object Interval
## Number of Packets per Object
## have to set page specific attributes before createPage
## have to set object specific attributes after createPage
$httpSession1 setDistribution interPage_ Exponential 1 ;#in sec
$httpSession1 setDistribution pageSize_ Constant 1 ;# number of objects/page
$httpSession1 createPage
$httpSession1 setDistribution interObject_ Exponential 0.01 ;# in sec
$httpSession1 setDistribution objectSize_ ParetoII 10 1.2 ;# number of packets

# uses default 
$httpSession2 createPage

$ns at 0.1 "$httpSession1 start" ;# in sec as well
$ns at 0.2 "$httpSession2 start"

$ns at 30.0 "finish"

proc finish {} {
	global ns
	$ns flush-trace
	puts "running nam..."
    # exec to run unix command
	exec nam out.nam &
	exit 0
}

# Start the simualtion
$ns run

 

dumbbell.tcl

# Created by Polly Huang
# Simple 4-node star topology
#        8    7       2    3
#           \ |       | / 
#        9 -- 1 ----- 0 -- 4
#           / |       | \
#        10   11      6    5   

proc create_topology {} {
global ns n num_node
set num_node 12

for {set i 0} {$i < $num_node} {incr i} {
	set n($i) [$ns node]
}

$ns set src_ [list 2 3 4 5 6]
$ns set dst_ [list 7 8 9 10 11]

# EDGES (from-node to-node length a b):
$ns duplex-link $n(0) $n(1) 1.5Mb 40ms DropTail
$ns duplex-link $n(0) $n(2) 10Mb 20ms DropTail
$ns duplex-link $n(0) $n(3) 10Mb 20ms DropTail
$ns duplex-link $n(0) $n(4) 10Mb 20ms DropTail
$ns duplex-link $n(0) $n(5) 10Mb 20ms DropTail
$ns duplex-link $n(0) $n(6) 10Mb 20ms DropTail
$ns duplex-link $n(1) $n(7) 10Mb 20ms DropTail
$ns duplex-link $n(1) $n(8) 10Mb 20ms DropTail
$ns duplex-link $n(1) $n(9) 10Mb 20ms DropTail
$ns duplex-link $n(1) $n(10) 10Mb 20ms DropTail
$ns duplex-link $n(1) $n(11) 10Mb 20ms DropTail

$ns duplex-link-op $n(0) $n(1) orient left
$ns duplex-link-op $n(0) $n(2) orient up
$ns duplex-link-op $n(0) $n(3) orient right-up
$ns duplex-link-op $n(0) $n(4) orient right
$ns duplex-link-op $n(0) $n(5) orient right-down
$ns duplex-link-op $n(0) $n(6) orient down
$ns duplex-link-op $n(1) $n(7) orient up
$ns duplex-link-op $n(1) $n(8) orient left-up
$ns duplex-link-op $n(1) $n(9) orient left 
$ns duplex-link-op $n(1) $n(10) orient left-down
$ns duplex-link-op $n(1) $n(11) orient down
}
# end of create_topology